What is a positive way to help motivate parents to do some sort of activity(s)?

I forgot to add some important details: both my parents are COPD. My mom has significant arthritis in her knees and uses a walker to get to and from the bathroom and a wheelchair outside the house. And my dad will go outside to fill the bird feeders. Other than that they are both armchair heroes with eyes wide-open or napily closed throughout the day long.
Thank you Countrymouse Give a hug for your well replied comment!

You can start a club (where the parents live) for card playing. Many seniors (neighbors) love playing cards and it is a good social activity. You may even want to join in when time allows.

Your forum ID of Surfhero slightly troubles me - I hope you're not quite that ambitious for your parents??!!

I sympathise with the difficulty of finding the right balance between leaving them to melt into their armchairs v. straying over the line into bullying them. Of course we want to "encourage" activity, it's a question of knowing how hard and far to push it.

Getting my mother to do gentle physio daily was a long and tedious uphill struggle. She was always too tired, not in the mood, or wanting to wait until she had "just" done something else such as watch a TV programme or drink her tea. A similar story with "Singing For The Brain," a choral group which I did honestly think she would love until she flatly refused to get in the car to go to it four weeks running. But given a trip to a safari park last September, which involved getting up at half past six in the morning, clambering on board a Land Rover and being bounced around over fields for three hours, she was miraculously wide awake and enthusiastic.

From this I infer that if they want to do something that they can do, they will; and if they don't, they won't. You may worry about failing to keep them active, but in the end - barring dementia - it is and ought to be their informed choice. So offer them the information and the opportunities, and beyond that sit easy.

What works for us is an "active adults" exercise class. I go with him and we both work-out for 45 minutes. Then while I do my elliptical for 20 minutes, he does about 10 minutes on a stationary bike. While I finish with 20 minutes of upper-body resistance training, he goes to the café and finds a seat for us to eat lunch together. We do this 3-times a week, for some 13 years now. After we finish, he's so much more alert. It's not easy getting him there-- wake up, eat, shave, shower, shampoo, dress, remember where the garage is, etc. This ends up being our major activity together. I coach him every step of the way. I usually run a couple errands on the way home, while he sleeps in the car. This has kept us both healthy for many, many years.

For my parents, I haven't got a strict schedule (since my work has erratic schedule) but I do give them a weekly "heads up" IE, I tell them: on Mon & Tues I can't come over but Darcy will be there Mon afternoon, I will be there on Weds, and again Sat and Sunday we go to church. On that sample week just given, I make sure Darcy gets them out of house (Mon) and I get them out on Weds and Sun. Sat I might bring hot pizza, or an unbaked lasagna, or if they feel up to going out, I will take them to Olive Garden but only if we can ge there before 4pm, too crowded otherwise. My point is I try to make sure they get out of the house at least 3x per week. The rest of the time I know for surely they are only eating, watching TV, doing laundry (mom does it every day! ) reading the daily newspaper (thr paper version)....etc. there isn't much else they can do, they both having trouble with arthritis in hands/knees so they're not able to garden, or do woodworking or needlework. They don't like sudoku or crosswords. Seems like many of their activities are not very "active" but what could they do? Besides walking around shopping, which is done out of the house. So have to get them out, and 1x is Darcy (paid caregiver) and the other 2x is me (free caregiver daughter). I hope some others can offer suggestions.... as for me I hope by my 90's I finally have time and can still do some hobbies, but seeing my folks with all their arthritis is not too promising. Maybe I can paint? Maybe they would like to paint! I will get them some paints! Hey, I'm going to see if they want to go to Michael's tonight!

I have tried some of the suggestions but some of the others I have not. Very helpful thank you for your insight.

Usually you just go for it without asking "do you want to" or "can we".
Tell them "we will stop at.. and do.. and then we will go for lunch/dinner together.."
A routine can greatly help, visit same time everyday or so, trying to do an activity, might as well take a picture of you with parent and later use it to show what you did and it'll help to be active again.

Big problem for me with my dad. He enjoys reading the paper, doing crossword puzzle and watching tv. Sometimes I can get him to do a puzzle. I try and get him to do little things under the pretense of helping me. Emptying silver wear from dishwasher, swifter under kitchen table (he uses walker and wheelchair). He likes shopping outings but otherwise could sit in his chair all day. I have an egg timer and every hour he must get up and walk thru the house 3x. He is in control of the timer but I do check to make sure he resets it. I also am curious to see what other suggestions people come up with. This is not an easy one!